Internal-combustion-engine piston



Aug. 18, 1925. G. Y. LAUCHIN INTERNAL COMBUSTION ENGINE PISTON Filed Aug. 13, 1925 IN VEN 1 9R.

ATTORNEYS.

Patented Aug. 18, 1925.

UNITED STATES "GEORGE Y. LAUcnn or GREEN BAY, WISCONSIN.

INTERNAL-COMBUSTION-ENGINE PISTON.

Application filed August 13, 1923. Serial No. 657,081.

of its objects to provide a piston which will automatically compensate for the differences inthe rates of expansion of the piston walls and the cylinder walls.

Asis well known in this 'art, much difliculty has heretofore been encountered in properly fitting the pistons of internal combustion engines within their cylinders so as to produce a'gas tight fit, while. at the same 7 time roviding sufiicient clearance to keep the sliding friction at a minimum, and to permit of the expansion and contraction of the cylinders andpistons. If the pistons were made too loose in an endeavor to provide for the expansion thereof, they would wobble when the engine was cold, and would not form a gas-tight joint with the cylinder walls, with the result that fuel is lost, piston and cylinder walls soon become worn and out of round, and excessive noise develops. On the other hand, if the pistons are made too tight when the cylinders of the motor heat up, theexpansion of pistons will cause them to bind and score the cylinder walls.

The problem was further increased by the present tendency to construct the pistons of aluminum allo which, of course, is much lighter in weig t than the grey iron usually employed in the cylinder castings, for the pistons being of a lighter weight and marterial and having a diflerent rate of-expansion from the cylinder walls, they would expand much more readily than the cylinders,

thereby tending to cause the said pistons to bind.

, It is the primary object of the present invention to provide a piston which may be formed of a relatively light weight of aluminum or other alloy, which will overcome the above difiiculties in that it may be made sufliciently tight within the cylinders to form a as [tight joint, ,while at the same time it w1ll, due to the provision of resilient portions, adjust itself to any differences in the rates of expansion of the piston and cylinder walls, so as to prevent excessive friction between the two and the consequent binding and scoring of the cylinders.

lVith the above and other objects in view, which will appear as the description proceeds, the invention consists in the novel details of construction and combinations of pants more fully hereinafter disclosed, and particularly pointed out in the appended claims.

Referring to the accompanying drawings in which like numerals designate like parts in all the views;

Figure 1 is a side elevational View of a piston constructed in accordance with the present invention;

Fig. 2 is a central vertical sectional view, taken approximately on the plane indicated by the line 2-2 of Fig. 1, and,

Fig. 3 is an inverted plan view, partly broken away, of the parts shown in Figs. 1 and 2. v

In the said drawings, the numeral 5 indicates the head of the piston, which is preferably hollowed out as indicated at 6, see Fig. 2, and which may be provided with the usual packing ring grooves 7, extending circumferentially around the head. Integral with the said head is a pair of oppositely disposed chordal webs 8, extending downwardly, and having formed integrally therewith the connecting rod pin bearingS 9.

As above stated, the webs 8 form substantial chords of the circle, constituting the outer circumferenceof the piston head, and at each end of each of the webs 8 there is secured thereto, as by the integral or rigidbers 11 are rigidly connected to the bearings 9by the vertically extending webs 14, the

lower portions of which may be split as indicated at 15, to render the same resilient,

and to thereby permit the yielding of the skirt members 11, as will presently appear.

Thesaid skirt members may be provided with the circumferentially extending oil grooves 16, adapted to facilitate the lubrication of the parts, as will be readily understood. I

In actual practice the head 5 of the cylinder may be made of slightly lessdiameter than the skirt portions 11, if defar as the head is concerned. The lower skirt portion of the cylinder may be made of such dimensions as to produce a free sliding fit when the motor is cold, and when the motor heats up, the expansion of the piston, if at a different rate than that of the cylinder walls, will be automatically compensated for, due to the resilient connections between the skirt members 11 and the head of the piston, the said resilient connections comprising theu-shaped portions and the split webs 14.

Pistons constructed in accordance with the above disclosure will be found to provide a motor in which leakage of gas past the pistons is substantially eliminated, while at the same time, due to the resilience of the skirt portions of the pistons, there will be no undue friction and binding or scoring of the cylinder walls. 7

While one form of the invention has been illustrated and described it is obvious that those skilled in the art may vary the details of construction as well as the arrangement of parts without departing from the spirit of the invention, and therefore it is not wished to be limited to the above disclosure except as may be required by the accom 'panying claims,

\ What is claimed is:

1. A piston of the class described comprising a head provided with a plurality of depending spaced parallel chordal webs; a divided skirt member having cut-away portions; and integral substantially I U- shaped resilient connections between the ends of saidwebs and the upper side edges of said skirt member.

2. A piston of the class described comprising ahead having a pair of spaced depending chordal Webs provided with wrist pin bearings; a divided skirt cut-away opposite said webs; substantially U-shaped resilient connections between the ends of said webs and,the top of said skirt; and additional resilient connections between the lower portion of said skirt and said wrist pin bearings.

3. A piston of the class described comprising a head having a pair of integral spaced substantially T-shaped webs, the lower'vertical portions of which are split; and a divided skirt, the lower portions of which are connected to said split portions of said webs, while the upper portions of said skirt are connected to the ends of the horizontal portions of said webs bysubstantially U-shaped resilient connections.

'In testimony whereof, I affix my signature.

GEORGE Y. LAUCHIN. 

